The Influence of the Prey Physiological Stress Response on Predator-prey Interactions

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

Predator-prey interactions are a common feature of ecological systems and have been shown to drive their structure, function, and dynamics. Even so, critical knowledge gaps exist with respect to the mechanisms that underlie the prey's behavioral, physiological, and morphological response to predation risk, including how those responses influence the performance of predator. This study will use a model system (predatory larval dragonflies and tadpole prey) to understand how predation risk and food availability modulate the anti-predator response. This study will build upon a large body of experimental research that shows that the fear response of the tadpoles governs both their behavioral (e.g., activity) and morphological (e.g., tail growth) responses to predators. The approach taken will be integrative and interdisciplinary, with endocrinology measurements used in conjunction with laboratory experiments and computational models of optimal prey responses. This study will include K-12 classroom visits, the development of new college courses, and the provision of student research opportunities all aimed at improving the preparedness of students, especially under-represented groups, for entering and succeeding in STEM fields. The specific aims of this research are to determine: 1) how the prey neuroendocrine stress response operates over time and is shaped by complex predation environments and trade-offs; 2) how stress hormones govern the expression and integration of the prey phenotypic response (i.e., behavior, morphology) in an ecological context; and 3) how the prey phenotype influences predator-prey interactions. The intellectual merit of this proposal centers on our use of a model ecological system, novel experiments, and novel optimality modeling to shed insight into how physiology and development regulate plasticity in adaptive traits and what the ecological impacts of this regulation are. Identifying the proximate physiological mechanisms that govern phenotypic expression will enhance the general understanding of the phenotypic range that prey are capable of achieving in response to predators, the tradeoffs that influence costs and benefits of particular phenotypes, and how predators induce prey phenotypes. Identifying the mechanisms underlying prey phenoptypic plasticity also will help clarify the role of nonconsumptive effects in ecological communities. Ultimately, the findings generated herein will provide important insight into the linkages that exist among the environment, an organism's physiological response and its resulting phenotypic plasticity, and the fitness consequences to both prey and predator.